We will use this button to select a spline within the scene. All of the trees are created within the area defined by this spline. The spline MUST be a closed spline for this operation to work correctly. If it is a compound spline, which includes several sub-splines, the trees will be created inside all of the valid areas enclosed by the splines.

With the "Clear" button, we can remove all of the splines used for the inclusion of trees.

Note: The "include" spline will also define the Z position of all the trees if we are not using a 3D surface to place the trees upon. However, all trees will be placed at the same height position as the highest vertex of the spline.

Exclude

The splines that are selected with this option define the areas where trees WILL NOT be generated, excluding them from the include spline. This spline must be a closed spline and may also be composed of sub-splines.

The plugin will require more time and effort to calculate the placement of the trees when you use exclude splines (the plugin first has to build all trees within the included area and then it must ignore those trees which are within the exclusion areas). Therefore, it is best not to use this option. In most scenes, it is possible to define complex areas by only using an include spline. An example of replacing a combination Include and Exclude spline with a single include spline can be seen below:

Spline Falloff

In some scenes it may be useful to modify the trees near the edges of the area. These options allows us to define density and scale curves for spline distance. Press the Edit Curve button to edit them. There are separate options to define distance ranges for Include and Exclude splines.

Important Note: The default range values are 0, that will not create any falloff effect. So, to use this feature, you must enable the "Active" checkbox and set a range value greater than 0.

Following Path

With this option, trees are created surrounding the selected spline. Following and include spline are exclusive options, you can use only one of them at time.

Realign Object

The Forest object must be aligned with the area spline to use some features (such as facing Camera). To preserve this alignment, Forest links itself to the spline, so moving or rotating the spline will modify the Forest object too. If this alignment is broken (for instance, moving Forest but not the spline), use the "Realign Object" button to restore it.

If the "Auto realign" checkbox is enabled, picking a new Include or Following spline will always realign the Forest object with the specified spline.